Abstract
Molecular probes for lung cancer have greatly increased the understanding of the biology of this disease and the preneoplastic changes that precede it. They have confirmed and extended the clinical, pathologic, and biologic reasons for the primary division of lung cancers into small cell and non-small cell lung cancer types. Many molecular changes are present in lung cancers and involve dominant oncogenes and recessive growth regulatory genes. Clinical application of these markers will aid diagnosis, classification, and clinical management.